Composition containing poly-1,1-dihydroxyperfluorobutyl acrylate, silicon dioxide, carbon black and curing agent



United States Patent COMPOSITION CONTAINING POLY-1,1-DIHY.- DROXYPERFLUOROBUTYL ACRYLATE, SIL- was obtained at a temperature of 310 F. for 60 minutes. A relatively substantial amount of curing ingredients such as sulfur and triethylene tetramine were found necessary to produce the optimum physical properties in the final ICON DIOXIDE, CARBON BLACK AND CUR- 6 product. After curing, test specimens were prepared and N AGENT subjected to hot-oil aging to determine the usability of the compositions. 322,3 3 2: 352: g i g gfi sg ig gag z f gg fi The test results in the following table indicate not only th Ai Force the properties of those compositions which comprise the 10 invention, but also include examples of results obtained N0 Drawmg' APPhcatmn November 1957 using one or the other of the fillers above. The specific Sena] 695995 ingredients used and the quantities of each are: Poly-FBA, 5 Cl i (Cl, 260-285) 100 parts by weight; paraffin, 1 part by weight; Cab-O-Sil, as shown in table; Philblack O, as shown in table; sulfur, This invention relates to polymeric compositions, and 15 1 part by weight; triethylene tetramine, as shown in table. is more particularly concerned with an improved group Cab-O-Sil is silicon dioxide, a product of Godfrey L. of polyfluorobutyl acrylate polymer compositions. Cabot, Inc., and Philblack O is a high abrasion furnace Because of increased speeds and greater power requirecarbon black, a product of Phillips Chemical Co. The ments in newly developed aircraft, it has become necesparafiin employed is in the form of a soft, hydrocarbon sary to increase the operating temperatures in aircraft 2O wax and is a product of Shell Chemical Company.

Ingredients Original Properties After Aging 500 Hrs. at 350 F. After Aging 500 Hrs. at 400 F.

Hard- Hard- Hard- Oab-O- Phil- Tensile Elonness, Tensile Elonness, Swell, Graek- Tensile Elonness, Swell, Crack- Sil black TETA Strength gation Shore Strengt gation, Shore Percent tug Strength, gation, Shore Percent ing 0 p.s.i. Percent A p.s.i. Percent A p.s.i. Percent A 15 1.2 820 330 45 430 250 54 9.9 No a5 1.0 960 150 03 590 120 65 0.2 No

15 10 1.4 1, 230 390 57 640 300 00 5.5 No 290 00 72 3.8- No 10 1.4 1, 340 280 60 700 180 67 5.7 No 350 70 73 3.8 No

lubricating and hydraulic systems. With such tempera- These results were obtained by using an aging procedure ture increases, the presently used fluids were found to be unsatisfactory, and it was deemed necessary to employ ester-type lubricants and ester-type hydraulic fluids. Although such a change solved the problem presented, it also created a new problem. The esters in combination with the elevated temperatures were found to be very harmful to rubber component parts such as hoses, gaskets and the like. Accordingly, it was necessary to develop an improved rubber which could withstand the deleterious action of the esters for at least 500 hours at temperatures ofat least 350 F.

Therefore, it is an object of this invention to provide an improved rubber composition.

More specifically, an object of the invention is to provide a polymeric composition which exhibits increased resistance to the destructive action of ester-type fluids and high temperatures.

In solving the problem presented, the base polymer employed was poly-l.l-dihydroperfluorobutyl acrylate produced under the trade name Poly-FBA by the Minnesota Mining and Manufacturing Company. Although the specific examples hereinafter set forth all employ Poly- FBA, it should be understood the other and different acrylate polymers may also be employed.

Tests were run on Poly-FBA compositions wherein various fillers were used. While furnace black-filled polyfluorobutyl acrylate compositions generally display a poorer retention of physical properties upon hot-oil aging than silicon dioxide-filled compositions, the black-filled compositions usually have higher elongation, both before and after aging.

As a consequence of these facts, a series of polymeric compositions were prepared using both of the abovenamed fillers. Various quantities of each filler were used. The resulting compounds were milled and cured using standard procedures well known to those skilled in the art. A suitable cure for those set forth in the examples which consisted of suspending samples of the test specimens in test tubes. A synthetic diester oil was added, and the tubes were placed in an aluminum-block heater for the desired time interval. At the end of a given aging period, the tubes were removed from the aluminum block and allowed to cool for one hour. then taken from the oil, dipped quickly in acetone to remove any oil adhering to the surface, and blotted dry before tests were run. The stress-strain properties were determined with a Dillon Low-Range Tester used at a speed of 20 inches per minute, and hardness was observed on a Shore A-2 Durometer. Swelling was determined with a Klaus-Jolly balance. The percent swelling was calculated by comparing relative volumes before and after aging. The cracking was checked by visual observation with specimens flexed degrees.

The tabulated results of these tests make clear the superior over-all performance of the compositions of the invention. At 350 F., their tensile strength is considerably greater while the percentage of swelling is materially reduced. The elongation of the inventive com positions also compares favorably with those composi tions using only a single filler, and finally the hardness is well within the acceptable range. After hot-oil aging at 400 F, there is such a complete degradation of the single filler compositions that figures are not included. With both fillers used together, it will be noted that the physical properties of the compositions are still good, and no cracking is evident. Although specific data has been included for only two examples, it should be pointed out that other compositions may be prepared using fillers in proportions intermediate to those set forth herein.

From all of the foregoing it will be clear that my invention provides a rubber composition having heretofore unavailable resistance to degradation when exposed to lubricants at elevated temperatures. It is to be understood that the above described principle may be applied The samples were in other and different: ways by those skilled in the art without departing from the spirit and scope of the invention.

What is claim ed is; V v 7 LA polymeric rubber compositionconsisting 'es'sem tially of 100 parts by weight of poly-1,1-dihydroperfluorobutyl acrylate, from 10 to 15 parts by weight of silicon dioxide, from 10 to 20 parts by weight of carbon black,

and 1.4 parts by weight of triethylene tetramine.

2. A polymeric rubber composition as defined in claim 1, further including 1 part by weight of 'paraflin wax and sulfur. 3; A polymeric rubber composition consisting essentially of 100 parts by weight of poly-1,1-dihydroperfluoro butyl acrylate, 1 part by weight of parafiin wax, 15 parts by weight of silicon dioxide and 10 parts by weight of carbon black as fillers, and 1 part by weight of sulfur and 1.4 parts by weight of triethylene tetramine as curatives.

4. A polymeric rubber composition consisting essentially of 100 parts by weight of poly-1,1-dihydroperfluorobutyl acrylate, from 10 to 15 parts by weight of silicon dioxide, from 10 to 20 parts by weight of carbon black, and curing agents for the polymeric acrylate consisting of sulfur and triethylene tetramine, said agents comprising 2.4 parts by weight of said composition;

5; A polyineric rubber composition consisting essentially of 100 parts by weight of poly-1,1-dihydroperfluorobutyl acrylate, 1 part by weight of paraflin wax, 10 parts byweight of silicon dioxide and 20 parts by weight of carbon black as fillers, and 1 part by weight of sulfur and 1.4 parts by weight of triethylene tetramine as curativesh, References Citedin the file of this patent UNITED STATES PATENTS 2,209,928 Nowak et al July 30, 1940 

1. A POLYMERIC RUBBER COMPOSITION CONSISTING ESSENTIALLY OF 100 PARTS BY WEIGHT OF POLY-1,1-DIHYDROPERFLUOROBUTYL ACRYLATE, FROM 10 TO 15 PARTS BY WEIGHT OF SILICON DIOXIDE, FROM 10 TO 20 PARTS BY WEIGHT OF CARBON BLACK, AND 1,4 PARTS BY WEIGHT OF TRIETHYLENE TETRAMINE. 